(1. Key Laboratory of Shale Gas and Geo-engineering，Institute of Geology and Geophysics，Chinese Academy of Sciences，Beijing 100029，China；2. University of Chinese Academy of Sciences，Beijing 100049，China)
Abstract：To investigate the mechanical response of soil rock mixtures(SRM) with the oversized blocks，large-scale triaxial shear consolidated undrained(CU) tests under different confining pressures were conducted on the unconventional sample of soil rock mixtures with the volumetric block proportions(VBP) of 25%，35% respectively. The results showed that the volumetric change was still observed under the condition of undrained tests for the soil rock mixtures with the oversized blocks. The volumetric strain of soil rock mixtures with the volumetric block proportion of 35% showed the characteristics of shear contraction at the initial stage，the shear dilatation，the secondary shear contraction，and the shear dilatation once again at the higher confining pressures. The curves of the deviator stress against the axial strain are smooth under the volumetric block proportion of 25%. However the curves of the deviator stress against the axial strain have the zigzag shape under the volumetric block proportion of 35%. The jump phenomena of the stress，volumetric strain and pore water pressure were exhibited.